- #1
Maxim Nol
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Homework Statement
Hello everyone!
To simplify, I have a system whose transfer function looks like this:
G = (s^2-1) / (s^4-s^2-1)
It's unstable and I have to find a way to stabilize it using PID controller and/or lead/lag compensators.
Homework Equations
The Attempt at a Solution
So far I tried a simple PID controller (Kp + Ki/s + Kd*s), a PID controller with low pass filter (Kp + Ki/s + Kd*s/(1+N*Kd*s), a PID controller with multiple derivatives and integrators (P*I^m*D^n) but no luck.
I'm using MATLAB to solve it.
Root locus attached.
Could you give me any hints?
Thank you.